/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.dubbo.config.spring.extension;

import org.apache.dubbo.common.extension.ExtensionFactory;
import org.apache.dubbo.common.extension.SPI;
import org.apache.dubbo.common.logger.Logger;
import org.apache.dubbo.common.logger.LoggerFactory;
import org.apache.dubbo.common.utils.ConcurrentHashSet;
import org.apache.dubbo.config.DubboShutdownHook;
import org.apache.dubbo.config.spring.util.BeanFactoryUtils;

import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.beans.factory.NoUniqueBeanDefinitionException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.event.ContextClosedEvent;

import java.util.Set;

/**
 * SpringExtensionFactory
 */
public class SpringExtensionFactory implements ExtensionFactory {

  private static final Logger logger = LoggerFactory.getLogger(SpringExtensionFactory.class);

  private static final Set<ApplicationContext> contexts = new ConcurrentHashSet<ApplicationContext>();
  private static final ApplicationListener shutdownHookListener = new ShutdownHookListener();

  public static void addApplicationContext(ApplicationContext context) {
    contexts.add(context);
    if (context instanceof ConfigurableApplicationContext) {
      ((ConfigurableApplicationContext) context).registerShutdownHook();
      DubboShutdownHook.getDubboShutdownHook().unregister();
    }
    BeanFactoryUtils.addApplicationListener(context, shutdownHookListener);
  }

  public static void removeApplicationContext(ApplicationContext context) {
    contexts.remove(context);
  }

  public static Set<ApplicationContext> getContexts() {
    return contexts;
  }

  // currently for test purpose
  public static void clearContexts() {
    contexts.clear();
  }

  @Override
  @SuppressWarnings("unchecked")
  public <T> T getExtension(Class<T> type, String name) {

    //SPI should be get from SpiExtensionFactory
    if (type.isInterface() && type.isAnnotationPresent(SPI.class)) {
      return null;
    }

    for (ApplicationContext context : contexts) {
      if (context.containsBean(name)) {
        Object bean = context.getBean(name);
        if (type.isInstance(bean)) {
          return (T) bean;
        }
      }
    }

    logger.warn(
        "No spring extension (bean) named:" + name + ", try to find an extension (bean) of type "
            + type.getName());

    if (Object.class == type) {
      return null;
    }

    for (ApplicationContext context : contexts) {
      try {
        return context.getBean(type);
      } catch (NoUniqueBeanDefinitionException multiBeanExe) {
        logger.warn("Find more than 1 spring extensions (beans) of type " + type.getName()
            + ", will stop auto injection. Please make sure you have specified the concrete parameter type and there's only one extension of that type.");
      } catch (NoSuchBeanDefinitionException noBeanExe) {
        if (logger.isDebugEnabled()) {
          logger
              .debug("Error when get spring extension(bean) for type:" + type.getName(), noBeanExe);
        }
      }
    }

    logger.warn("No spring extension (bean) named:" + name + ", type:" + type.getName()
        + " found, stop get bean.");

    return null;
  }

  private static class ShutdownHookListener implements ApplicationListener {

    @Override
    public void onApplicationEvent(ApplicationEvent event) {
      if (event instanceof ContextClosedEvent) {
        DubboShutdownHook shutdownHook = DubboShutdownHook.getDubboShutdownHook();
        shutdownHook.doDestroy();
      }
    }
  }
}
